Richard Wordingham wrote: My favourite examples are ฆ่า 'kill' and เฒ่า 'old'.
ເຖົ້າ-->
เฒ่า ,
ຂ້າ -->
ฆ่า 
Nice to see this! I was not aware of this phenomenon and your examples are really lovely (and demonstrative for me).
Matching Sanskrit devanagari with the ... Lao script, possible but not that trivial... I'll come back soon to the actual heading of this thread, but, for a second Lao letters...:
Richard Wordingham wrote:Before the Lao spelling reform, there was an attempt to add or revive the missing letters needed to write Pali (and Sanskrit?) in the Lao script rather than the Tham script. Apart from this, I get the impression the Lao spelling reform had little effect on the complement of the Lao script as used for Lao.
I fear that my past view on the spelling reform was simply wrong. The reason why I would like to show you as follows:
ภรรยา [
พันยา,
พันระยา] {
ພັນຣະຍາ, (
ພັນລະຍາ)} (
ส.
ภารฺยา;
ป.
ภริยา)
Actually in this way I came in contact with Lao dictionaries: I tried to find out more about how to use sattha akson (Thai/Siamese) without knowing its rules in those days. Modern Lao spelling was a big help for the further understanding. Based on this experience, I obviously (?) concluded wrong that part of the Lao spelling reform was
to eliminate the letters needed to write Pali (and Sanskrit?), thus, applying "sattha akson Lao" on the (posited) older (and more tua/to than 27 [?] comprising) phayansana, and declaring the transcription result as "Lao according to the modern spelling rules".
I understand your remark, now, in that way, that there was no older phayansana and that it just had 27 tua/to for more than 40 years (?) only.
Thus, I thought
เฒ่า-->
ເຖົ້າ but not
ເຖົ້າ-->
เฒ่า. But since
เฒ่า has obviously no Sanskrit etymology
Thus, Lao letters (to write Lao language) were never (at least for significantly more than 40 years ago) used to transliterate (but only to transcribe) PaliSanskrit terms.
Then, besides I have to renew my view on the Lao spelling reform, I have to reconsider my view on Thai letters themselves:
A letter like
ภ, pho samphao, was it "always" in the Thai/Siamese phayanchana? And if not, were these letters introduced for means of transliterating Pali/Sanskrit?
Must add that
ซ โซ่ is not needed to write Sanskrit, or Pali. But I understand now that not
ໂສ້ (and not Northern Thai
โส้), but, rather,
โซ่ is more likely to be the result of a 'spelling reform' - or should it be called spelling accident?